Tank for chromium-plating baths



April G, 1929. Q JEN5EN- y 1,709,022

TANK FOR CHROMIUM PLATING BATES Filed April 12, 1927 Iig. l.

Patented Apr. 16, 11929 14*ourre-n srA'rss PATENT fortiori.

LEO D. JENSEN, or cIIIcAeo, ILLINOIS, nssIGNon; BY IvinsNn ASSIGNMENTS, To

UNITED CHROMIUM, INeoRPonA'r'ED,

DELAWARE.

OF NEW YORK, N. Y., A COR11"ORATIOJ- OF TANK FOR CHROMUM-PLATIN G BATHS.

Application inea April 12,

This invention relates -to tanks for electrodeposition and provides improvements there- Chromic acid solutions containing acid t radicals are used for vthe electrodeposition of chromium, and earthenware and lead lined wooden tanks have been usually used for containing such solutions. Earthenware tanks are somewhat fragile and limited inthe in sizes which can be obtained. l Lead tanks are attacked by the solution and develop perforations in time. Moreover, in metal tanks, or metal-lined tanks, stray currents reach the tanks or tank'linings.

l have found that a most satisfactory tank can be provided, meeting all physical requirements and capable of being made in any size and capacity desired, by making the tanks of iron orsteel and facing these with sheets to of glass, or equivalent material not attacked by the solution, and acting as insulators or current-shields between the cathode and the tanlcmetal. By reason of the high cui-rent densities used in chromium plating, and the no /eonsequent large currents used in-a bath, the saving by cutting down the stray currents, and the advantage of directing all of the eur rent onto the cathode, are of very material consequence. rfhis elimination of stray currents is important not only because of energy eii'dciency, ut particularly because it'has a dehnite effcct upon the degree to which arti cles being plated are covered, and upon the nature and uniformity of the chromium deposit.,

An embodimentof the invention is illu-v strated in the accompanying drawing, of which embodimenty lligure l is a longitudinal sectional view, and l llt aontal section. y

Referring toA said drawing, numeral l designates the metal tank (steel on iron), which is conveniently fabricated of sheets, which maybe of suitable size and number to give the size desired and of requisite strength. 'llhe sides and ends of the tank are designated bynumerals l2, 13, lt and 15, and the bottoni by liti. A rim 20, conveniently of angle iron may be usedl to strengthen the upper edges of the tank.

VGlass sheets are laid on the bottom and against the sides and .ends of the tank. Nu-

`made of wire-glass,

sides and ends of the tank.

means such as strips of metal 32 1927. Serial No. 183,024.

moral designates the sheet laid on the bottom, 26 the sheets laid against the ends and 27 the sheets laid against the sides. Where the areas to be covered are relatively large,

the glassshects 25, 2G, 27 are preferably laid 1n sections 29, so as to be readily replaced when broken. The sheets also are preferably so as not to fall in pieces broken, as the breaking of a Vsheet into pieces is not of material consequence as long as the pieces retain their position against the Simple fastening means suice for securl Ing the plates 26, 27 against the sides and ends of the tanks, it only being necessary to hold the sheets against their own weight. -Simple bent or hooked over the edges or rim of the tank and over the upper edges of the glasssheets are suiiicient and are easily removed and replaced inhibited by the shield constituted by theA glass sheets 25, 26, 27.

'llanks constructed as described also lend Bti themselves to heating (or cooling) from without, thus dispensing with coils (usually of lead) `in the bath, showing comparatively rapid deterioration and receiving leakage of current from the electrodes. To this end, the tank is conveniently'provided with an outv v A' side heating (or cooling) means, here shown llig., 2 is a topplan view fpartially in horias a simple gas heater 40 beneath the underside of the tank. [t acket il-2 is,conveniently formed around the sides and ends of the tank for coniningthe temperature' controlling medium against the sides and ends. rlhis jacket as shown is'open, 'as this is suflicient with the construction shown. A variety of arrangements for eiecting the tem perature control through the sides, ends and/or bottom of the tank may obviously be chosen. 4Inside heating (or'coolimr) means .may however be employed if desire Another advantage of the'present tank is that cathode articles yaccidently coming lil@ ' against A(or purposely supported against) the sides or bottom of the tank are protected against thel effect of short circuits, which. owing'to the high current densities used in chromium plating', and consequent large -currents employed, give rise to dangerous short circuits.

The invention may receive other embodi ments-than that chosen for illustration, and

equivalents of the parts and materials mentioned in the claims are included in their sco e.

what is claimed is 1. A tank for chromium plating baths, of metal, with glass sheets covering the inside metal faces, adapted to cut oli' stray currents, and to prevent short-circuits between the electrodes and the inside of the metal tank,

and means -for holding said sheets in (glace, said means holding the upper edgesy said glass sheets.

tank for chromium plating bath-s, of i metal, with glass sheets covering the inside metal faces, adapted to cut olf stray currents, and to prevent short-circuits between the electrodes and the inside of the metal tank, said glass sheetsl being in sections.

In witness whereof, I have hereunto signed my name.

Lilol D. JENSEN. 

